Electronic factory SMT production line times the speed chain should be programme

You just took over the SMT workshop management, is not always encountered this bad thing? Patch machine running happily, but the circuit board stuck in the conveyor belt grinding, or inexplicably by the static electricity through the chip?Don't be so quick to dump on equipment vendorsToday we chatter through the SMT speed chain combat programme - the right choice of this thing yield rubbing up; screwed up, millions of mounter directly into the scrap metal! Today we nag through the SMT speed chain of the actual programme - this thing is selected correctly, the yield of rubbing up; screwed up, millions of mounter directly into scrap metal!

First, why SMT production line must use the speed chain? Ordinary conveyor belts can not?

​Ordinary conveyor belts are a disaster site in an SMT shop! Don't believe me:

  • ​out of step with the paceBonder can hit 5000 dots per minute and the belt line only climbs 2 metres per minute? Equipment dry and other materials, capacity directly cut
  • ​The Static FeverPVC belt friction generates electricity easily breaking 10,000 volts, precision BGA chips die when touched.
  • ​positional drift: 0.5mm IC pins to align pads, belt slippage? Paste crooked a piece of loss of one hundred thousand!

Case in the face: a factory in Dongguan with ordinary roller line, SMT yield stuck in 92% dead on the go. After changing to triple speed chain + anti-static design.Yield rate soared to 97%The cost of scrapping the light saves $800,000 a year.

To put it bluntly, the speed multiplier chain is to equip the SMT production line with aturbocharger--The speed of the work plate is 2.5~3 times that of the chain, which perfectly matches the rhythm of the mounter. Not to mention that it can also play double track parallel, U-shaped layout of these tawdry operation!

Second, the design of high-efficiency multiplier chain system 3 big tough tricks

Don't be fooled by your suppliers! This is how you have to match the multiplier chain for SMT production lines:

​▌ The core parameters are stuck on these three.​

  1. ​Speed must be ≥ 8 m/min: Measurement of the mounter out of the board interval of 0.8 seconds, times the chain of slow traffic jam!
  2. ​Positioning accuracy ±0.1mmAluminium rails with optical locating pins are just what is needed, ordinary carbon steel is finished when it deforms.
  3. ​Anti-static grade 10^6~10^9Ω: Carbon black compound rubber for rollers, metal parts all anodised

​▌ Layout to avoid these two sinkholes​

  • ​Don't make a long line.SMT workshop space is at a premium.U-shaped or circular layout land-saving 30%It also reduces the number of workers running
  • ​Drive segments in the middle: 10m+ line body driven at both ends? The chain is ripped into a twist! Centre drive + self-tensioning pulley for stability!

​▌ Automated articulation is critical​

make a copy of
SMD → Speed Chain Transition: retrofit**Top lift**(Height difference ≤3mm)
↓
Reflow soldering outlet → Double speed chain: Matching**Buffer storage section**(bumper design)
↓
AOI inspection station: installed**Pneumatic stopper**(Response time <0.3 seconds)  




Tears of blood lesson: a factory in Shenzhen did not install the buffer section, reflow soldering out of the board into a domino, 300 pieces of daily loss






Third, anti-static practical programme: don't wait for the chip to smoke before regretting!


SMT workshop electrostatic protection is not a label and that's it!The triple defence has to be welded.::


​① The body of the speed chain is anti-static.​


    

  • Roller surface resistance.10^6~10^8Ω-cm(Taking monthly megohmmeter measurements)
    • 

  • Grounding point every 2 metres of chain: earth resistance<4Ω(Ordinary workshop grounding >10Ω? Pull the copper row separately!)
    • 

  • Antistatic Bakelite for Workplace Boards: Surface LaminationGreen Conductive Rubber Sheet(Never use wood panels! It fails if the humidity changes)
    • 



​② Synergistic prevention and control of the environment​


    

  • ​Humidity deadening 45%~65%RH: Static voltage doubles when below 40%! Air conditioner vents put humidifier
    • 

  • Ionic fans every 3 metres: static voltage at outlet0±50VMonthly alcohol scrubbing of tungsten needles
    • 



​③ Personnel anti-dumbing design​


    

  • Conductive table mat on the operating table: connected to 1MΩ resistor series grounding
    • 

  • Wrist strap connected to the alarm monitor: resistance over 10MΩ automatic red light
    • 

  • ​Chemical fibre clothing = walking detonators: Work clothes all cotton + anti-static shoes (a factory staff wearing down jackets, cuffs friction discharge through the whole batch of motherboards)
    • 





Fourth, maintenance: don't wait for the chain to get stuck before you cry!


doubled speed chainThree months without maintenance, failure rate skyrockets 70%! These three tricks are followed:


​▶ Daily must-do​


    

  • Alcohol wipes on rollers: antistatic layer fails when exposed to grease and dirt
    • 

  • Listen to the noise: bearing dry grinding sound? Stop the line immediately and add lithium grease
    • 



​▶ Weekly Highlights​


    

  • Multimeter grounding: chain link to grounding stake＞10Ω? sandpaper sanding paint layer
    • 

  • Check the straightness of the track: laser level sweep, deviation within 2 metres > 1mm hurry to adjust
    • 



​▶ Monthly Tips​


    

  1. Chain stretch test: calipers measure 10 chains, elongation>3% directly replace the new one.
    2. 

  2. Tensioner wheel reset: spring pressed to the bottom? Life expired
    3. 

  3. Drive motor physical examination: insulation resistance <10MΩ? disassemble and clear toner!
    4. 





​ask and answer questions for oneself​

​Q: Why do I still have problems when I follow the manual?​

A: 80% of them are planted inEnvironmental dustSMT workshop solder paste dust drills into the chain and abrades the links more than sandpaper-!Vacuuming the track chute every month!






​And finally, a little bit of truth.::

Don't believe in the "expensive is good" nonsense! The chrome-plated chain of a big international brand won't last more than half a year in the pickling workshop.Stainless Steel Spray ChainUse it for five years without rust. Remember that.A design that suits the characteristics of the production line is 100 times more important than a brand logo.After all, we are not in the business of buying luxury goods. After all, we engage in manufacturing is not to buy luxury goods, save hundreds of thousands to buy ribs it does not smell good?

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